"Another important point is that you can point at the AOL OpenID service from any web page you own in order to turn its URL into an OpenID. The minimal requirements are basically that you have some AOL or AIM account, and that you add a couple of links to your document's HEAD.

OpenID starts with the concept that anyone can identify themselves on the Internet the same way websites do-with a URI (also called a URL or web address). Since URIs are at the very core of Web architecture, they provide a solid foundation for user-centric identity."